A semiconductor light emitting element which causes a direct transition-type semiconductor to carry out a recombination light emitting by injecting carriers on the basis of a p-n junction has attracted attention as a next-generation illumination light source. It is basically required that the light emitting semiconductor device for lighting emit a white light which is close to sunlight. As the semiconductor white light source, there are a three primary colors (RGB) element array, a quasi-white light source on the basis of color-mixing of a blue light emitted from a light emitting element and a yellow light emitted from a phosphor, and a three primary color phosphor excitation light source on the basis of an ultraviolet light emitting element and the like.
In the white light source using the phosphor, it is necessary to uniformly carry out a color mixing of a light emitting element output light, a phosphor output light or an output light between multicolor phosphors.